Your choice of capacitors brand can cause a big difference in sound and I would not blame the tolerance for it. Just another thing to complicate matters more.
Hehe, yea, I guess it can be a little daunting for some people, but the DIY projects you've shown us so far have been pretty impressive. Would it be the Heco Direkt 2-way speakers in your profile? Cool looking speakers. I see the crossover posted online, looks pretty average, Chinese metallized polyester capacitors, mostly iron core inductors, cement resistors, even an electrolytic capacitor doing some job, not too impressive for a $3300 speaker, but not unusual either. You'd probably want to trace out the schematic first and decide where upgrades would be most useful. Inductors can be a problem since they are often not off-the-shelf values, so you may have to buy the next size bigger and remove some windings to get the value you need. People often just build a new crossover with all new parts and point-to-point wiring on a wood or fiberglass board, and then replace the old crossover. I almost decided to go that route, but knew I could use the bottom of the board to fit the new capacitors since it is on standoffs, so just went that way. But I did toy with the idea of making new crossovers and leaving them external, does give you a lot of flexibility that way, but speakers are in the living room so that would get a little tacky without building some nice enclosures. Heco Direkt 2-way crossover ... My old crossover showing mounting on bottom of cabinet... In my case, I stripped all the parts off the board except for two of the inductors, and then relocated one inductor, changed the other iron core inductor to air core, and replaced all the resistors and capacitors, so didn't save much by using the old board...
Just a random rhetorical question...would you be annoyed if you opened up your $300 phono stage and it was instead the little board you found inside? I was thinking good reviewer bait would be to put a placebo $0.15 DIP chip covering tiny sot-23s.
Yeah, the Hecos. I've seen that crossover image before and thought they deserved better. I wouldn't mind doing external crossovers for them and assembling one could be pretty fun, but I do have visions of accidentally putting a thumb through one of the 11 inch cones trying to get it out. It's exactly the kind of thing I'd do. I believe Heco & Magnat are essentially the same company, based in Germany with their products built in China. The crossovers on all of their speakers that I've seen are woeful. This YouTube channel has done teardowns of quite a few Magnat speaker products. The money is certainly going toward the things the customer can see.
I'm still working in the stimulator. That's just a realization of how small one channel might be made (but it's not a phono preamp). SMT 1% PPS capacitor sticks to the solder iron: out $3. An artisanal point-to-point single-sided proto, if you must, not quite small enough to mount in the tonearm carriage: There's many logistical design questions to finalize it seems when you have to order assembled instead of hand-picked, like do I use four caps for one to increase precision, make a little R2R (actually C-2C) ladder so I can hand-trim $2 capacitor traces out of the circuit to match to 0.1%, or why not bake four pre modules and simply match those together in a mixer, which actually wins monte carlo. How to pick out best 2 of 4 opamps per package.. Do I design it just for me, or would people want this 3" from the phono jack, and who cares when vinyl stinks 100x worse as soon as you drop the needle. 1kHz THD+N with cart load at 10mV RMS, vs. Doug Self "NE5534A for lowest noise RIAA" in blue. (takes a game of solitaire to simulate, since it has to run past power supply startup, using capacitor models from manufacturer as complicated as op amps)
Oh wow you have Quicksand - Slip on vinyl, killer album and rare, nice! Great amp too, I have the one below that, the 2200 in black as well. Sorry, off topic..
Got it. One of these days I need to try your simulator again and see how the curves look when I take the RIAA components to 5% or even 10% (gasp!) tolerance-acceptable extremes. I imagine the curve gets quite curvy.
Two-capacitor feedback RIAA, when you let the capacitors go +/- 5%: Lesson: don't try tweaking your phono stage with random audiophile capacitors you can't condition and measure. (Now a high-order high-gain Chebyshev filter's high-Q stage, where this 20dB peak needs to be accurate... you don't want it off by 5%)
Made a heavier counterweight yesterday and like the results much better, gets it back closer to the pivot, don't really need any additional effective mass with this heavy arm. First picture with stock counterweight and aux weight all the way at end of arm, second with single new weight much closer to pivot (stock weight in foreground on plinth), and third picture a closeup of counterweight, which is just an extra stock weight I had on hand, wrapped with a layer of 0.075" lead sheet and silicone adhesive (I like the way the ceramic arm tube turns into a Jedi lightsaber with the camera flash ) ...
After gluing it up and letting it dry, I chucked it in the drill press to clean it up, and then sanded the faces, which broke through the thin plating to the brass underneath that you see. I actually thought it was stainless steel, so wasn't expecting that, but went ahead and finished leaving the brass fully exposed. Not sure what I'll do, may just polish it, kinda matches the brass I have in the arm wand so doesn't look like a complete f*&!up
I've been thinking about building a Muffsy phono stage, routing the PCB myself. I don't know why, just to see how it would work, I guess. I don't want to learn to work w/ Gerber files, so instead took the PDF of the copper side, imported that into my Vectric software, traced it, and then added some test tool paths. I only did a few drill holes in the traces in the upper left-hand corner, to see how it might work. Below is a simulation of what it may look like. I don't have the correct bit (would need a .005D ball nose for this) but I'm thinking about getting one or two and seeing how this might go. I might add my RCA jacks right to the board, as I've used panel mount RCA jacks in the past and kind of find them to be a PITA if you need to disassemble and make changes. Also they can be hit or miss in terms of quality.
Yeah that is what sort of surprised me, it got (as my daughters would say) matchy matchy w/ the arm. I like it a lot.
I decided to see how small I could make a good phono stage... the answer is 2cm x 2.4cm, under an inch. Two sets of outputs, since making balanced-out would take two more resistors and and it was already enough work to not put any audio through vias. (on the top is the footprint of just a barrel power connector for reference) Some of the caps are for removing to tune the tolerance. Remove two 100pf from each channel to get the actual response: Not actually going to build this, because +/- 0.05dB RIAA and 0.003% distortion isn't so interesting without subsonic, EMI control, rumble subtraction, mono, channel balance and crosstalk controls, LDRs and voltage controlled capacitors, loading correction...
@Phil Thien , if your going to machine the copper traces on fiberglass PC boards, make sure to use carbide drills and end mills. Even carbide gets worn out quickly, the glass fill is very abrasive. BillWojo
Thanks Bill. I've actually routed circuit boards previously, just really a fairly crude design used for my PLLXO (Passive Line Level XOver). This will be the first time I try to use someone else's design.
Mr. DeVore talks very openly about his barter transactions, saying he wouldn’t be able to afford his gear except through barter trades. I wonder if he knows barter transactions are still taxable as income? I expect he doesn’t or he wouldn’t be so open about them.
This link shows the spare Xerxes top board I am refurbishing. https://i.postimg.cc/85RY8QHm/2-B0-EA69-A-74-D6-446-D-AD69-A9-CEBCFD1172.jpg It had an SME cut out, but I returned it to Roksan/Rega geometry by filling the hole. Rather than using all filler the excess space near the arm socket was filled with small rocks! Should be better with rock music! A similar pile of small rocks sits to the rear of the picture to give a sense of scale.
https://i.postimg.cc/dtfcjFSh/29572518-F06-E-4-EB4-93-F7-7-DE5917924-A4.jpg Here is the refurbished board with zero sag and funky ‘stealth’ black paint. It’s a fashionable colour now so why not? The top and matching wood surround look pretty cool together IMO. I still have the Roksan ‘you have paid for precision equipment......’ sticker, which will be replaced correctly!
That is a cool project, followed some of it in your turntable thread. Ya know, if you just put img tags around the image links like in the code box below, they will display in your post and people don't have to go to the host site to see them. No biggie, just informational Code: [img]https://i.postimg.cc/85RY8QHm/2-B0-EA69-A-74-D6-446-D-AD69-A9-CEBCFD1172.jpg[/img] [img]https://i.postimg.cc/dtfcjFSh/29572518-F06-E-4-EB4-93-F7-7-DE5917924-A4.jpg[/img]
Thanks Davey, you’re a star. I’m not too bad with a file or a bit of sand paper, but I’m just a sad oldie with computer tech! Note the slight imitated wood grain I scribed into the filler around the arm socket. This top board is just an interim experiment before the all new hardwood top board I am preparing for the Xerxes.
